Well bridging tool



April 28, 1964 J. c. MASON WELL BRIDGING TOOL Filed Sept. 12, 1960 1'INVEN TOR.

(/ZMES t; Mme 4 United States Patent 3,138,787 WELL BRIDGING TGGL JamesC. Mason, 3521 Lime Ava, Long Beach 7, Calif. Filed Esept. 12, 196i),Ser. No. 55,364 1 Claim. (Cl. 166-187) This invention relates to packersfor use in oil and gas wells or the like to efiect a seal with the wallsurface therein, and more particularly to an improved packing orbridging tool for forming a seal with the interior wall of the well borefor separating one portion of the well from another portion thereof,such that, for example, cement can be poured into the well bore abovethe tool when the well is abandoned.

In many well drilling operations it is sometimes necessary to bridge orplug a pipe, tubular conduit or an uncased well bore at somepredetermined point. It is common practice to establish such a bridge orplug by placing a body of cement or the like at the desired point in theconduit or hole and allowing the same to harden in place. When it isnecessary to remove such a plug, however, a time-consuming and expensivedrilling operation is required, which is particularly objectionablewhere it is necessary to bridge the conduit or well casing at successivepoints from time to time as in testing operations of the type well knownto the art.

It is a principal object of the present invention to provide a simpleand efficient retrievable bridge plug formed from an expandablesheath ofrubber or the like which is provided with a fluid-pressure connectionfor the introduction of fluid under pressure to the interior of thesheath to distend or expand the same and wedge it in place within thewell bore.

It is another object of the present invention to provide a bridging plugof the above type which may be removed from its installed position.

Another object of the present invention is to provide an improved meansfor expanding the flexible sheath utilized as a bridging element in thetool.

It is a further object of the present invention to provide a bridgingtool of the type described, the operation of which is not dependent uponthe existence of a particular pressure within the well bore beingplugged.

Yet another object of the present invention is to provide a plug of thetype described which may be utilized as a retrievable plug but may alsobe easily filled with cement or like material to form a permanent plugin the well bore.

A still further object of the present invention is to provide animproved construction for a well bore bridging plug which is simple andeconomical to manufacture and use.

The novel features which are believed to be characteristic of thepresent invention both as to its organization and method of operation,together with further objects and advantages thereof, will be betterunderstood from the following description considered in connection withthe accompanying drawing in which a presently preferred embodiment ofthe invention is illustrated by way of example. It is to be expresslyunderstood, however, that the drawing is for the purpose of illustrationand description only and is not intended as a definition of the limitsof the invention.

In the drawing:

FIGURE 1 is a partially diagrammatic view in elevation of a bridgingplug in accordance with the present invention as utilized in a wellbore;

FIGURE 2 is a view in elevation of the apparatus of i the presentinvention with the expandable bag partially expanded by pressure offluid Within the well;

FIGURE 3 is a partial view in elevation of the valving arrangement ofthe present invention taken along line 3-3 of FIGURE 2; and

FIGURE 4 is a view corresponding to FIGURE 2 but with the bridging plugfully expanded in place within the well bore and with the setting drillstring removed therefrom.

Referring now to the drawing, the present invention includes in generalan inflatable bag A of rubber or similar elastomeric material which isgenerally cylindrical in configuration with a closed lower end and anopening defined at the upper end thereof. A tubular member B extendslongitudinally throughout a substantial portion of the length of the bagand is connected by a connecting and valve assembly C to a drill stringD. In the utilization of the tool, the tool is extended within the wellbore from a drilling rig E suitable for the purposes for which thebridging plug is to be applied as shown in FIGURE 1.

Referring now particularly to FIGURES 2 and 3, the inflatable bag A hasa relatively small opening 11 at the upper end thereof and a neck 12with a bead 13 is formed in order that the bag can be sealingly engagedupon the tubular member B. The bag at the neck 12 thereof is sealinglyengaged with the tubular member by means of a collar 14 which is formedof drillable material such as aluminum. The tubular member B extendsthroughout a substantial portion of the length of the inflatable bag andthrough the opening 11 at the upper and thereof to a position above thebead 13 when the bag is relatively oriented as shown in the drawings.The tubular member B has an inside diameter adapted to be mated by meansof the connecting and valve member C to a drill string D of the typewell known to the art. Exteriorly of the bag, that is, above the bead13, a longitudinally extending slot 15 is provided from the upper end 16of the tubular member downward to a position which is still above andexteriorly of the bag. A transverse slot 17 is then formed at the lowerend of the longitudinal slot 15 and is turned upward at 18 to form aJ-slot 24 of the well-known type. A one-way check valve 20 is pivotallymounted at the open lower end of the tubular member B and is soconstructed and arranged with respect to the end of the member thatfluid may pass downward through the tubular member but is blocked frompassing from the interior of the bag upward through the tubular memberas shown in FIG- URE 4.

The connecting and valving assembly C includes a connecting tubularmember 22 which is adapted to be connected at the upper end thereof tothe lower end of the string D by a collar 21 as shown in FIGURE 1. Theoutside diameter of the connecting tube 22 is approximately equal to theinside diameter of the tubular member B and is slidably mateabletherewith. A pin 23 is afiixed to the exterior wall of the connectingtube 22 and is mateable with the J-slot 24 formed by the slots 15 and 17as previously described. Thus, the connecting tubular member 22 can belongitudinally affixed to the tubular member B by slidably engaging theconnecting tube 22 with the tubular member B such that the pin 23 passesdownward in the portion 15 of the J-slot after which it can be rotatedalong the transverse slot 17 and raised and locked into the upwardlyextending portion 18 of the J-slot. Fluid ports 25 are provided throughthe wall of the tubular connector 22 at a longitudinal posi tbion whichis above the upper end 16 of the tubular memer B.

A slidable valving sleeve 27 is positioned within the connecting tube 22for longitudinal sliding movement with respect thereto. The valvingsleeve 27 is positioned within the tubular connector 22 at alongitudinal position above the ports 25. That is, the lower end 28 ofthe sleeve in its upper position as shown in FIGURE 3 is above the ports25. A cylindrical collar 30 is affixed within the tubular connector 22at a position beneath the fluid ports 25 to provide a shoulder 31beneath the ports. A compression spring 32 is positioned upon theshoulder 31 between the stationary shoulder and the slidable sleeve 27.The sleeve 27 is thus normally urged upward to the position shown inFIGURE 3 at which the bottom surface 28 of the sleeve is above theports. The relative location of the collar 30 and the height of thespring 32 is such that the sliding sleeve valve 27 is movable down-Wardly to a closed position as shown in phantom in FIG- URE 3 at whichthe lower end 28 is beneath the ports 25 while the upper end 34 is abovethe ports 25 to effectively close the ports against the passage of fluidtherethrough. A shoulder is provided at the upper end 34 of the sleeve27 of such area that when contacted by fluid flowing downwardly therebya suflicient downward force is exerted on the shoulder to move thesleeve 27 down- Wardly against the force of the spring 32. This actionis subsequently explained in greater detail in conjunction with adescription of the operation of the invention.

The tubular member B as well as the collar 14 are formed of drillablematerial such that they can be easily washed over or drilled away whenit is necessary to remove the bridging plug from the well bore.

Thus, in operation the apparatus of the present invention is utilized byaflixing the connecting valve assembly C to a drill string D by meanswell known to the art. As shown in FIGURE 1, the connecting tubularmember 22 with the valve assembly included therein is assembled orconnected to the tubular member B by inserting the pin 23 into theJ-slot as shown in FIGURE 2. The inflatable bag A is deflated and ispreferably wrapped tightly about the tubular member B as shown in FIGURE1 for descent into the hole. The bridging plug is lowered into the wellbore as shown in FIGURE 1 to the position at which the bridge is to beformed. When the apparatus has reached the proper depth within the wellbore, if well fluid exists within the bore, it will pass inwardlythrough the ports 25 and downwardly through the collar 36, the tubularconnecting member 22, the tubular member B and outward through the valve26 to the interior of the inflatable bag A to cause the bag to bepartially inflated. The extent of inflation will depend upon wellpressure existing Within the bore. When the well pressure has beenequalized such that the pressure at the exterior of the drill string issubstantially equal to the pressure of the interior of the inflatablebag, additional fluid can be pumped downwardly from the drillingapparatus E through the drill string, through the sliding sleeve member27, collar 39 and downward through the tubular member B. As fluid underpressure is admitted down the drill string the force of the pressureupon the upper shoulder 34 of the sliding sleeve 27 will force thesleeve downward from the position shown in FIGURE 3 to the closedposition shown in phantom line at which it blocks the fluid ports 25 sothat fluid progressing down the drill string cannot pass outwardlythrough the ports and must pass downward through the tubular member 13to the interior of the inflatable bag A. The elastomeric bag A isinflated to a desired pressure by the fluid after ports 25 close, andexpands to wedge in the bore hole or frictionally grip the sides thereofto remain in a fixed position in the bore hole.

It can be seen that the spring 32 can be determined to allow closure ofthe fluid ports at any desired fluid pressure within the drill string.Thus the fluid under pres Sure progresses outwardly from the tubularmember B through the valve 2t? and into the inflatable bag until the bagis inflated to the required pressure. When the fluid pressure is removedfrom the interior of the drill string, the valve 29 will close to entrapthe fluid within the bag due to the tendency of the fluid in the bag toflow to the lower pressure Zone in the tubing. As such flow of fluidtends to take place from the bag A to tubular member B, valve Zil whichacts as a check valve, closes. The drill string together with thetubular connecting members and valve assembly can then be removed fromthe inflatable bag A and tubular member B by rotating the drill string apartial turn to remove the pin 23 from the J-slot 24. Cement 41) canthen, for example, be poured into the Well bore where it will set andharden upon the inflatable bag to form an effective bridge in the wellbore. When it is necessary to remove the bridge, a drilling or wash-overoperation can be easily performed since all portions of the toolremaining within the well bore are of drillable material or are portionsof the elastomeric inflatable bag.

What is claimed is:

A well bridging tool capable of being lowered into a Well bore to adesired depth by a tubing string and a portion of said tool thereafterinflated by fluid under pressure to grip said well bore to the extentthat said portion of said tool will support fluid cement thereaboveuntil said cement sets, which tool includes:

(a) an inflatable resilient bag having a closed lower end and an upperend in which an opening is defined;

(b) a tubular member that extends into the confines of said bag throughsaid opening;

(0) means for holding the upper extremity of said bag in sealing contactwith said tubular member;

(d) means for releasably connecting the upper portion of said tubularmember to the lower end of said tubing string; and

(e) a check valve on said tubular member that permits fluid to bedischarged downwardly into said bag until said fluid is at a desiredpressure therein and said bag has expanded to grip said well bore, saidcheck valve closing upon upward flow of fluid from said bag to saidtubular member due to the pressure on fluid in said tubular member beinglowered below the pressure on fluid in said bag, with said fluid in saidbag being trapped therein as a result of the closing of said check valveboth before and after said tubular member has been released from saidtubing string.

References ited in the file of this patent UNITED STATES PATENTS1,523,286 Railsback Jan. 13, 1925 2,399,125 Lehnhard Apr. 23, 19462,603,293 Lynes July 15, 1952 2,922,478 Maly Jan. 26, 1960

